Add test coverage for cmp_default_heuristics

src/host/alsa/mod.rs

@@ -9,11 +9,11 @@ use crate::{
     SupportedBufferSize, SupportedStreamConfig, SupportedStreamConfigRange,
     SupportedStreamConfigsError,
 };
+use std::cmp;
 use std::convert::TryInto;
 use std::sync::Arc;
 use std::thread::{self, JoinHandle};
 use std::vec::IntoIter as VecIntoIter;
-use std::{cmp, mem};
 use traits::{DeviceTrait, HostTrait, StreamTrait};
 
 pub use self::enumerate::{default_input_device, default_output_device, Devices};
@@ -446,7 +446,9 @@ struct StreamInner {
     // Minimum number of samples to put in the buffer.
     period_len: usize,
 
+    #[allow(dead_code)]
     // Whether or not the hardware supports pausing the stream.
+    // TODO: We need an API to expose this. See #197, #284.
     can_pause: bool,
 
     // In the case that the device does not return valid timestamps via `get_htstamp`, this field

src/lib.rs

@@ -633,6 +633,75 @@ impl SupportedStreamConfigRange {
     }
 }
 
+#[test]
+fn test_cmp_default_heuristics() {
+    let mut formats = vec![
+        SupportedStreamConfigRange {
+            buffer_size: SupportedBufferSize::Range { min: 256, max: 512 },
+            channels: 2,
+            min_sample_rate: SampleRate(1),
+            max_sample_rate: SampleRate(96000),
+            sample_format: SampleFormat::F32,
+        },
+        SupportedStreamConfigRange {
+            buffer_size: SupportedBufferSize::Range { min: 256, max: 512 },
+            channels: 1,
+            min_sample_rate: SampleRate(1),
+            max_sample_rate: SampleRate(96000),
+            sample_format: SampleFormat::F32,
+        },
+        SupportedStreamConfigRange {
+            buffer_size: SupportedBufferSize::Range { min: 256, max: 512 },
+            channels: 2,
+            min_sample_rate: SampleRate(1),
+            max_sample_rate: SampleRate(96000),
+            sample_format: SampleFormat::I16,
+        },
+        SupportedStreamConfigRange {
+            buffer_size: SupportedBufferSize::Range { min: 256, max: 512 },
+            channels: 2,
+            min_sample_rate: SampleRate(1),
+            max_sample_rate: SampleRate(96000),
+            sample_format: SampleFormat::U16,
+        },
+        SupportedStreamConfigRange {
+            buffer_size: SupportedBufferSize::Range { min: 256, max: 512 },
+            channels: 2,
+            min_sample_rate: SampleRate(1),
+            max_sample_rate: SampleRate(22050),
+            sample_format: SampleFormat::F32,
+        },
+    ];
+
+    formats.sort_by(|a, b| a.cmp_default_heuristics(b));
+
+    // lowest-priority first:
+    assert_eq!(formats[0].sample_format(), SampleFormat::F32);
+    assert_eq!(formats[0].min_sample_rate(), SampleRate(1));
+    assert_eq!(formats[0].max_sample_rate(), SampleRate(96000));
+    assert_eq!(formats[0].channels(), 1);
+
+    assert_eq!(formats[1].sample_format(), SampleFormat::U16);
+    assert_eq!(formats[1].min_sample_rate(), SampleRate(1));
+    assert_eq!(formats[1].max_sample_rate(), SampleRate(96000));
+    assert_eq!(formats[1].channels(), 2);
+
+    assert_eq!(formats[2].sample_format(), SampleFormat::I16);
+    assert_eq!(formats[2].min_sample_rate(), SampleRate(1));
+    assert_eq!(formats[2].max_sample_rate(), SampleRate(96000));
+    assert_eq!(formats[2].channels(), 2);
+
+    assert_eq!(formats[3].sample_format(), SampleFormat::F32);
+    assert_eq!(formats[3].min_sample_rate(), SampleRate(1));
+    assert_eq!(formats[3].max_sample_rate(), SampleRate(22050));
+    assert_eq!(formats[3].channels(), 2);
+
+    assert_eq!(formats[4].sample_format(), SampleFormat::F32);
+    assert_eq!(formats[4].min_sample_rate(), SampleRate(1));
+    assert_eq!(formats[4].max_sample_rate(), SampleRate(96000));
+    assert_eq!(formats[4].channels(), 2);
+}
+
 impl From<SupportedStreamConfig> for StreamConfig {
     fn from(conf: SupportedStreamConfig) -> Self {
         conf.config()